Sunday, February 22, 2009

Truth, Solar Costs, and David Biello

As a teen age boy, i often walked a mile and a half to the Oak Ridge Public Library on summer days. There I would read a number of magazines and journals, and from their contents i constructed my world. I held Scientific American in very high regard then, and read each issue eagerly. i always thought of Scientific American as the gold standard of reliability.

No more. Last week David Biello posted a story on reliable solar electricity in the SA electronic edition. The story offered an account of the Andasol 1 solar thermal power plant. The Andasol 1 facility represents an advance in solar thermal technology. It offers heat storage in low cost molten salts. The molten salt technology offers several improvement over conventional Solar thermal technology. Stored heat allows the facility to load follow and produce peak energy. It also allows operators to to smooth out the dips and spikes in electrical generation caused by alternatively cloudy and sunny conditions. With molten salt energy storage electricity can be generated at night. Biello tells us how much electricity Andasol 1 produces - 50 MWs - the number of hours it can produce electricity - 7.5 - and its cost - $380 million. But then something goes very wrong in Biello's account. Solar Millennium AG, Andasol'sbuilder acknowledges that Andasol is

currently remunerated with a feed-in tariff of just under € 0.27/kWh.

That is $0.34 a KWh. Indeed capital cost of the Andasol 1 facility is $7600 per KW, a 50% priemium over thye current high end estimate of the cost of conventional nuclear power.

Biello does not reveal this shocking cost to his readers. instead he inserts a completely misleading statement from National Renewables Energy Laboratory engineer Greg Glatzmaier suggesting that "Electricity from a solar-thermal power plant costs roughly 13 cents a kilowatt-hour, according to both with and without molten salt storage systems". This is of course utter nonsense, as anyone who would make the effort to check on the cost and generating capacity of recently constructed or proposed solar facilities. The NREL has a history of making highly optimistic statements about solar costs. Statements that appear to have no relationship to project balance sheets. According to Biello, Glatzmaier told him that Molten Salt storage only cost $50 per kilowatt-hour to install. This is very misleading. Storage may not greatly add to the cost of the facility, but increasing the amount of heat captured does. The daily electrical output of a solar thermal facility without storage is equal to about 4.5 hours of electricity at its rated capacity. In order to increase that amount to 7.5 hours at rated capacity, more heat has to be captured, and this is done by increasing the size of the very expensive array of mirrors used to reflect sunlight onto the heat capturing mechanism of Andasol 1. Rest assured that installing the extra mirrors cost more than $50 per kilowatt. Glatzmaier 13 cents figure is what is called a canard - something that leads us away from true knowledge of the cost of solar thermal generated electricity. The electricity from Aldasol 1 costs well over twice 13 cents.

Now it is clear that the proponents of a solar power would like us to believe that it can be delivered cheaply, if only a hugh subsidy is given to solar manufacturers. if only they are given a chance the manufacturers will bring the price down. This of course is a scam, at the tax payers expense. It is clear that Biello is promoting the scam. What is not clear is whether Biello is knowingly using the authority of Scientific American to promote the scam, or whether he lacks the intelligence to understand the deception. What ever is the case David Biello has no business writing about energy for a science magazine that wishes to maintain a reputation for quality.

People change, values change, institutions change. Sometimes the changes are for the better, sometimes the changes are neither good nor bad, but some changes are decidedly for the worse. It is clear that Scientific American has changed for the worse. It is no longer the reliable and responsible voice I put my trust in as a teen age boy. I previously pointed to the anti-nuclear propaganda of David Biello in the Scientific American Electronic edition. The rot of Scientific American is so far advanced that Biello has not been fired as his incompetence would require. Instead the editors of Scientific American allow Biello continues to disregard truth and behave like the hack he is, pretending that distorted, and dishonest propaganda is fact. It is to the everlasting shame of Scientific American that its editorial leadership has allowed this to happen.

6 comments:

"The daily electrical output of a solar thermal facility without storage is equal to about 4.5 hours of electricity at its rated capacity. In order to increase that amount to 7.5 hours at rated capacity, more heat has to be captured, and this is done by increasing the size of the very expensive array of mirrors ..."

I think you're misreading their claims. "50 MW" seems to be the power of the electrical generator, not of the mirror array. Rather than upsizing their mirror array, they've down-sized their generator.

Solar Millennium says Andasol has "a gross electricity output of around 180 GWh per year", or 21 MW-yr per year, which seems plausible: 510,000 meters of collector x ~1kW/m² of incident sunlight x ~0.15 conversion efficiency (sunlight->heat->electricity) x ~8hr/day = 25 MW. So, their number is in the ballpark. Maybe optimistic, but only the size of the mirror array is a hard number.

Bill in order to increase storage time win an aray you either have to decrease the generation output, or increase the size of the array, The cost per rated KW for the Andasal facility is neasrly twice that of a typical ST facility. At the same time, the output suggests a capacity factor that is about 2/3rds greater than that of a typical no storage facility. Enlarging the array or decreasing the size of the generator yields the same change in output.

Yes, and as I said, 50 MW seems to be the generator output, not the peak output of the mirrors. That's why their implicit capacity factor is so high — 40%! Their claim for their thermal storage is that its capacity is 50 MW x 7.5 hr = 375 MW-hr. Which at Sci.Am.'s claimed $50/kW-hr is costing ~$20 million of the total $380 million.

Cheap thermal-energy storage has implications for nukes too (assuming it works, of course). They could run the reactor at full power at night, and store the heat to generate power during the following afternoon–evening peak demand period.